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Omotuyi IO. Ebola virus envelope glycoprotein derived peptide in human Furin-bound state: computational studies. J Biomol Struct Dyn 2014; 33:461-70. [PMID: 25347780 DOI: 10.1080/07391102.2014.981207] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Ebola virus (EboV) is currently ravaging West Africa with estimated case fatality rate of 52%. Currently, no drug treatment is available and immunoglobulin therapy is still at the rudimentary stage. For anti-EboV drug development, druggable viral and host protein targets, including human Furin are under intense investigation. Here, molecular dynamics simulation was performed on Apo-Furin, meta-guanidinomethyl-Phac-RVR-Amba-bound, and two EboV glycoprotein (GP) 494-TGGRRTRREA-503/Furin complexes (Accurate and one amino acid shift alignment). The results of the simulation established ligand-induced desolvation of Furin active site and structural compactness. Accurately aligned EboV-GP peptide exhibited a tighter binding mode with Furin and showed 1.5- and 3.0-fold MMPBSA binding free energy estimate compared with the displaced peptide and inhibitor, respectively. The difference in free energy was traced to the difference in contribution of threonine residues of the peptides. Furthermore, Furin subsites I conferred substrate specificity and ligand binding accuracy. Accurately aligned peptide trapped active site His194 side chain into gauche (-) (+60(o)) χ1-dihedral compared with gauche+ (-60(o)) in other biosystems while Asp153 is trapped in gauche+ (-60(o)) in ligand bound not Apo state. Ramachandran plot showed that the scissile Arg8 of the accurately aligned peptide showed β conformation distribution as apposed to 310R, αL, and 310L. Finally, the active site proximal Na(+) binding is dependent on substrate peptide occupancy of the active site but detaches in the absence of a ligand. In conclusion, Furin might represent candidate drug target for Ebola virus disease treatment via therapeutic target of the active site and Na(+) binding pocket.
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Affiliation(s)
- I Olaposi Omotuyi
- a Department of Pharmacology and Therapeutic Innovation , Graduate School of Biomedical Science, Nagasaki University , Nagasaki , Japan
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52
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Invasive potential of melanoma cells correlates with the expression of MT1-MMP and regulated by modulating its association with motility receptors via N-glycosylation on the receptors. BIOMED RESEARCH INTERNATIONAL 2014; 2014:804680. [PMID: 25180193 PMCID: PMC4144153 DOI: 10.1155/2014/804680] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 07/23/2014] [Indexed: 01/01/2023]
Abstract
Matrix remodeling and invasion of basement membrane are the major determinants of malignant progression. Matrix degrading enzymes play a pivotal role in this process and have been shown to be regulated at multiple levels. Using high metastatic B16F10 and its invasive variant B16BL6 cells, we previously demonstrated that the expression of β1,6 branched N-oligosaccharides promotes cellular adhesion on different matrix components which in turn induces secretion of MMP9. The present investigations report that although the two cell lines do not differ in the expression of uPAR, expression of MT1-MMP is significantly higher on B16BL6 cells. Analysis of the transcripts of tissue inhibitors of matrix metalloproteinases (TIMPs) showed that expression of both TIMP1 and TIMP2 correlates negatively with the invasive potential of cells. CD44 and β1 integrin, the two important receptors involved in motility, were identified to carry β1,6 branched N-oligosaccharides in an invasive potential dependent manner. However, their glycosylation status did not appear to influence their surface expression. Although glycosylation on CD44 had no effect, that on β1 integrin significantly affected association of β1 integrin with MT1-MMP. The results thus demonstrate that the cancer cells use multiple mechanisms for degradation of matrix in a controlled manner to couple it with movement for effective invasion.
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Dahms SO, Hardes K, Becker GL, Steinmetzer T, Brandstetter H, Than ME. X-ray structures of human furin in complex with competitive inhibitors. ACS Chem Biol 2014; 9:1113-8. [PMID: 24666235 PMCID: PMC4026159 DOI: 10.1021/cb500087x] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
Furin inhibitors are promising therapeutics
for the treatment of
cancer and numerous infections caused by bacteria and viruses, including
the highly lethal Bacillus anthracis or the pandemic
influenza virus. Development and improvement of inhibitors for pharmacological
use require a detailed knowledge of the protease’s substrate
and inhibitor binding properties. Here we present a novel preparation
of human furin and the first crystal structures of this enzyme in
complex with noncovalent inhibitors. We show the inhibitor exchange
by soaking, allowing the investigation of additional inhibitors and
substrate analogues. Thus, our work provides a basis for the rational
design of furin inhibitors.
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Affiliation(s)
- Sven O. Dahms
- Protein
Crystallography Group, Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
| | - Kornelia Hardes
- Department
of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg
6, D-35032 Marburg, Germany
| | - Gero L. Becker
- Department
of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg
6, D-35032 Marburg, Germany
| | - Torsten Steinmetzer
- Department
of Pharmaceutical Chemistry, Philipps University Marburg, Marbacher Weg
6, D-35032 Marburg, Germany
| | - Hans Brandstetter
- Department
of Molecular Biology, University of Salzburg, Billrothstrasse 11, A-5020 Salzburg, Austria
| | - Manuel E. Than
- Protein
Crystallography Group, Leibniz Institute for Age Research-Fritz Lipmann Institute (FLI), Beutenbergstr. 11, 07745 Jena, Germany
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54
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Zile MR, Baicu CF, Stroud RE, Van Laer AO, Jones JA, Patel R, Mukherjee R, Spinale FG. Mechanistic relationship between membrane type-1 matrix metalloproteinase and the myocardial response to pressure overload. Circ Heart Fail 2014; 7:340-50. [PMID: 24395927 PMCID: PMC3961496 DOI: 10.1161/circheartfailure.113.000984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 01/02/2014] [Indexed: 01/08/2023]
Abstract
BACKGROUND Although matrix metalloproteinases (MMPs) were initially thought to result primarily in extracellular matrix degradation, certain MMP types, such as membrane type-1 (MT1) MMP, may also be involved in profibrotic cascades through hydrolysis of latency-associated transforming growth factor-binding protein (LTBP-1) and activation of transforming growth factor-dependent profibrotic signaling. The present study tested the hypothesis that MT1-MMP plays a direct role in the matrix remodeling response to a left ventricular (LV) pressure overload (PO) stimulus. METHODS AND RESULTS Wild-type (WT) and transgenic mice with cardiac-restricted MT1-MMP overexpression or MT1-MMP reduced expression underwent PO for 4 weeks. PO resulted in a 57% increase in LV mass (no change in LV end diastolic volume, resulting in an increase in the LV mass/volume ratio consistent with concentric remodeling), a 60% increase in MT1-MMP-mediated LTBP-1 hydrolysis and a 190% increase in collagen content in WT mice. Although LV mass was similar among WT, MT1-MMP overexpression, and MT1-MMP reduced expression after PO, significant differences in LV function, MT1-MMP-mediated LTBP-1 hydrolysis, and collagen content occurred. PO in MT1-MMP overexpression increased LTBP-1 hydrolysis (18%), collagen content (60%), and left atrial dimension (19%; indicative of LV diastolic dysfunction) when compared with WT. PO in MT1-MMP reduced expression reduced left atrial dimension (19%), LTBP-1 hydrolysis (40%), and collagen content (32%) when compared with both WT. CONCLUSIONS Despite an equivalent PO stimulus and magnitude of LV myocardial growth, altering MT1-MMP levels caused specific matrix-dependent changes in remodeling, thereby demonstrating a mechanistic role in the development of the maladaptive remodeling and myocardial fibrotic response to PO.
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Affiliation(s)
- Michael R. Zile
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Catalin F. Baicu
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Robert E. Stroud
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - An O. Van Laer
- Division of Cardiology, Department of Medicine, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Jeffrey A. Jones
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Risha Patel
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Rupak Mukherjee
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, and RHJ Department of Veterans Affairs Medical Center, Charleston, SC
| | - Francis G. Spinale
- University of South Carolina School of Medicine, and W.J.B. Dorn Department of Veterans Affairs Medical Center, Columbia, SC
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55
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Kang TH, Knoff J, Yang B, Tsai YC, He L, Hung CF, Wu TC. Control of spontaneous ovarian tumors by CD8+ T cells through NKG2D-targeted delivery of antigenic peptide. Cell Biosci 2013; 3:48. [PMID: 24354786 PMCID: PMC3903078 DOI: 10.1186/2045-3701-3-48] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Accepted: 11/14/2013] [Indexed: 11/30/2022] Open
Abstract
Background There is an urgent need to develop targeted therapies for the control of advanced stage ovarian cancer because it is the most deadly gynecologic cancer. Antigen-specific immunotherapy is a promising approach because of the potential of the immune system to specifically target tumors without the toxicity associated with traditional chemoradiation. However, one of the major limitations for antigen-specific cancer immunotherapy is the pre-existing immune tolerance against endogenous targeted tumor antigens that frequently evolves during carcinogenesis. Here, we described the creation of a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8+ T cell-mediated immune attack, thereby circumventing many aspects of immune tolerance. The tumor-homing module, NKG2D, specifically binds to NKG2D ligand that is commonly overexpressed in ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8+ T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment. Results We show that this therapeutic chimeric protein specifically loaded antigenic epitope onto the surface of NKG2D ligand-expressing ovarian tumor cells, rendering ovarian tumors susceptible to antigen-specific CTL-mediated killing in vitro. Furthermore, we show that intraperitoneal administration of our therapeutic chimeric protein followed by adoptive transfer of antigen-specific CD8+ T cells generates potent antitumor effects and significant accumulation of antigen-specific CD8+ T cells in the tumor loci. Conclusions Our findings have promise for bypassing immune tolerance to enhance cancer immunotherapy.
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Affiliation(s)
| | | | | | | | | | | | - T-C Wu
- Department of Pathology, School of Medicine, Johns Hopkins University, Bldg, CRBII Rm, 309, 1550 Orleans Street, Baltimore, Maryland 21231, USA.
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56
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Kwiatkowska A, Couture F, Levesque C, Ly K, Desjardins R, Beauchemin S, Prahl A, Lammek B, Neugebauer W, Dory YL, Day R. Design, synthesis, and structure-activity relationship studies of a potent PACE4 inhibitor. J Med Chem 2013; 57:98-109. [PMID: 24350995 DOI: 10.1021/jm401457n] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
PACE4 plays an important role in the progression of prostate cancer and is an attractive target for the development of novel inhibitor-based tumor therapies. We previously reported the design and synthesis of a novel, potent, and relatively selective PACE4 inhibitor known as a Multi-Leu (ML) peptide. In the present work, we examined the ML peptide through detailed structure-activity relationship studies. A variety of ML-peptide analogues modified at the P8-P5 positions with leucine isomers (Nle, DLeu, and DNle) or substituted at the P1 position with arginine mimetics were tested for their inhibitory activity, specificity, stability, and antiproliferative effect. By incorporating d isomers at the P8 position or a decarboxylated arginine mimetic, we obtained analogues with an improved stability profile and excellent antiproliferative properties. The DLeu or DNle residue also has improved specificity toward PACE4, whereas specificity was reduced for a peptide modified with the arginine mimetic, such as 4-amidinobenzylamide.
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Affiliation(s)
- Anna Kwiatkowska
- Institut de Pharmacologie de Sherbrooke, Department of Surgery/Urology Division, Université de Sherbrooke , 3001 12th Avenue North, Sherbrooke, Québec, J1H 5N4, Canada
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57
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Voura EB, English JL, Yu HYE, Ho AT, Subarsky P, Hill RP, Hojilla CV, Khokha R. Proteolysis during tumor cell extravasation in vitro: metalloproteinase involvement across tumor cell types. PLoS One 2013; 8:e78413. [PMID: 24194929 PMCID: PMC3806793 DOI: 10.1371/journal.pone.0078413] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 09/20/2013] [Indexed: 12/22/2022] Open
Abstract
To test if proteolysis is involved in tumor cell extravasation, we developed an in vitro model where tumor cells cross an endothelial monolayer cultured on a basement membrane. Using this model we classified the ability of the cells to transmigrate through the endothelial cell barrier onto the underlying matrix, and scored this invasion according to the stage of passage through the endothelium. Metalloproteinase inhibitors reduced tumor cell extravasation by at least 35%. Visualization of protease and cell adhesion molecules by confocal microscopy demonstrated the cell surface localization of MMP-2, MMP-9, MT1-MMP, furin, CD44 and αvβ3, during the process of transendothelial migration. By the addition of inhibitors and bio-modulators we assessed the functional requirement of the aforementioned molecules for efficient migration. Proteolytic digestion occurred at the cell-matrix interface and was most evident during the migratory stage. All of the inhibitors and biomodulators affected the transition of the tumor cells into the migratory stage, highlighting the most prevalent use of proteolysis at this particular step of tumor cell extravasation. These data suggest that a proteolytic interface operates at the tumor cell surface within the tumor-endothelial cell microenvironment.
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Affiliation(s)
- Evelyn B. Voura
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
- Department of Biology, Dominican College, Orangeburg, New York, United States of America
| | - Jane L. English
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Hoi-Ying E. Yu
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Andrew T. Ho
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Patrick Subarsky
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Richard P. Hill
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Carlo V. Hojilla
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
| | - Rama Khokha
- Ontario Cancer Institute, Princess Margaret Hospital, Toronto, Ontario, Canada
- * E-mail:
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58
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Dragulescu-Andrasi A, Kothapalli SR, Tikhomirov GA, Rao J, Gambhir SS. Activatable oligomerizable imaging agents for photoacoustic imaging of furin-like activity in living subjects. J Am Chem Soc 2013; 135:11015-22. [PMID: 23859847 DOI: 10.1021/ja4010078] [Citation(s) in RCA: 178] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Photoacoustic (PA) imaging is continuing to be applied for physiological imaging and more recently for molecular imaging of living subjects. Owing to its high spatial resolution in deep tissues, PA imaging holds great potential for biomedical applications and molecular diagnostics. There is however a lack of probes for targeted PA imaging, especially in the area of enzyme-activatable probes. Here we introduce a molecular probe, which upon proteolytic processing is retained at the site of enzyme activity and provides PA contrast. The probe oligomerizes via a condensation reaction and accumulates in cells and tumors that express the protease. We demonstrate that this probe reports furin and furin-like activity in cells and tumor models by generating a significantly higher PA signal relative to furin-deficient and nontarget controls. This probe could report enzyme activity in living subjects at depths significantly greater than fluorescence imaging probes and has potential for molecular imaging in deep tumors.
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Affiliation(s)
- Anca Dragulescu-Andrasi
- Molecular Imaging Program at Stanford and Bio-X Program, Stanford University School of Medicine, Stanford, California 94305, USA
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59
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Opposite roles of furin and PC5A in N-cadherin processing. Neoplasia 2013; 14:880-92. [PMID: 23097623 DOI: 10.1593/neo.121250] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 08/13/2012] [Accepted: 08/27/2012] [Indexed: 12/15/2022] Open
Abstract
We recently demonstrated that lack of Furin-processing of the N-cadherin precursor (proNCAD) in highly invasive melanoma and brain tumor cells results in the cell-surface expression of a nonadhesive protein favoring cell migration and invasion in vitro. Quantitative polymerase chain reaction analysis of malignant human brain tumor cells revealed that of all proprotein convertases (PCs) only the levels of Furin and PC5A are modulated, being inversely (Furin) or directly (PC5A) correlated with brain tumor invasive capacity. Intriguingly, the N-terminal sequence following the Furin-activated NCAD site (RQKR↓DW(161), mouse nomenclature) reveals a second putative PC-processing site (RIRSDR↓DK(189)) located in the first extracellular domain. Cleavage at this site would abolish the adhesive functions of NCAD because of the loss of the critical Trp(161). This was confirmed upon analysis of the fate of the endogenous prosegment of proNCAD in human malignant glioma cells expressing high levels of Furin and low levels of PC5A (U343) or high levels of PC5A and negligible Furin levels (U251). Cellular analyses revealed that Furin is the best activating convertase releasing an ~17-kDa prosegment, whereas PC5A is the major inactivating enzyme resulting in the secretion of an ~20-kDa product. Like expression of proNCAD at the cell surface, cleavage of the NCAD molecule at RIRSDR↓DK(189) renders the U251 cancer cells less adhesive to one another and more migratory. Our work modifies the present view on posttranslational processing and surface expression of classic cadherins and clarifies how NCAD possesses a range of adhesive potentials and plays a critical role in tumor progression.
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60
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Shiryaev SA, Chernov AV, Golubkov VS, Thomsen ER, Chudin E, Chee MS, Kozlov IA, Strongin AY, Cieplak P. High-resolution analysis and functional mapping of cleavage sites and substrate proteins of furin in the human proteome. PLoS One 2013; 8:e54290. [PMID: 23335997 PMCID: PMC3545927 DOI: 10.1371/journal.pone.0054290] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 12/10/2012] [Indexed: 01/15/2023] Open
Abstract
Background There is a growing appreciation of the role of proteolytic processes in human health and disease, but tools for analysis of such processes on a proteome-wide scale are limited. Furin is a ubiquitous proprotein convertase that cleaves after basic residues and transforms secretory proproteins into biologically active proteins. Despite this important role, many furin substrates remain unknown in the human proteome. Methodology/Principal Findings We devised an approach for proteinase target identification that combines an in silico discovery pipeline with highly multiplexed proteinase activity assays. We performed in silico analysis of the human proteome and identified over 1,050 secretory proteins as potential furin substrates. We then used a multiplexed protease assay to validate these tentative targets. The assay was carried out on over 3,260 overlapping peptides designed to represent P7-P1’ and P4-P4’ positions of furin cleavage sites in the candidate proteins. The obtained results greatly increased our knowledge of the unique cleavage preferences of furin, revealed the importance of both short-range (P4-P1) and long-range (P7-P6) interactions in defining furin cleavage specificity, demonstrated that the R-X-R/K/X-R↓ motif alone is insufficient for predicting furin proteolysis of the substrate, and identified ∼490 potential protein substrates of furin in the human proteome. Conclusions/Significance The assignment of these substrates to cellular pathways suggests an important role of furin in development, including axonal guidance, cardiogenesis, and maintenance of stem cell pluripotency. The novel approach proposed in this study can be readily applied to other proteinases.
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Affiliation(s)
- Sergey A. Shiryaev
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Andrei V. Chernov
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Vladislav S. Golubkov
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Elliot R. Thomsen
- Prognosys Biosciences Inc., La Jolla, California, United States of America
| | - Eugene Chudin
- Prognosys Biosciences Inc., La Jolla, California, United States of America
| | - Mark S. Chee
- Prognosys Biosciences Inc., La Jolla, California, United States of America
| | - Igor A. Kozlov
- Prognosys Biosciences Inc., La Jolla, California, United States of America
| | - Alex Y. Strongin
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail: (PC); (AYS)
| | - Piotr Cieplak
- Infectious and Inflammatory Disease Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail: (PC); (AYS)
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Targeted coating with antigenic peptide renders tumor cells susceptible to CD8(+) T cell-mediated killing. Mol Ther 2012. [PMID: 23183537 DOI: 10.1038/mt.2012.233] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The potency of immunotherapies targeting endogenous tumor antigens is hindered by immune tolerance. We created a therapeutic agent comprised of a tumor-homing module fused to a functional domain capable of selectively rendering tumor cells sensitive to foreign antigen-specific CD8(+) T cell-mediated immune attack, and thereby, circumventing concerns for immune tolerance. The tumor-homing module is comprised of a single-chain variable fragment (scFv) that specifically binds to mesothelin (Meso), which is commonly overexpressed in human cancers, including ovarian tumors. The functional domain is comprised of the Fc portion of IgG2a protein and foreign immunogenic CD8(+) T cell epitope flanked by furin cleavage sites (R), which can be recognized and cleaved by furin that is highly expressed in the tumor microenvironment. We show that our therapeutic protein specifically loaded antigenic epitope onto the surface of mesothelin-expressing tumor cells, rendering tumors susceptible to antigen-specific cytotoxic CD8(+) T lymphocytes (CTL)-mediated killing in vitro and in vivo. Our findings have important implications for bypassing immune tolerance to enhance cancer immunotherapy.
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62
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Brant KA, Leikauf GD. Dysregulation of FURIN by prostaglandin-endoperoxide synthase 2 in lung epithelial NCI-H292 cells. Mol Carcinog 2012; 53:192-200. [PMID: 23065687 DOI: 10.1002/mc.21963] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 08/07/2012] [Accepted: 08/27/2012] [Indexed: 11/08/2022]
Abstract
Because proprotein convertases (PCSKs) activate growth factors and matrix metalloproteinase, these enzymes have been implicated in non-small cell lung cancer tumor progression and aggressiveness. Previous studies indicate that one PCSK member, FURIN is overexpressed in NSCLC, but little is known regarding the mechanisms driving PCSKs expression during malignant change. We sought to determine whether prostaglandin-endoperoxide synthase 2 (prostaglandin G/H synthase and cyclooxygenase) (PTGS2) (aka COX2), whose expression is also frequently increased in NSCLC, differentially regulates PCSK expression and activity between normal (NHBE) and NSCLC epithelial cells (NCI-H292, NCI-H441, A549). NSCLC cells exhibit significantly greater cell-associated and secreted PCSK activity as compared with NHBE. The heightened activity is consistent with increased FURIN, PCSK4, and PCSK6 protein in the NCSLC cells. Inhibition of PTGS2 activity using NS-398 and siRNA decreased FURIN mRNA, protein, activity along with cell proliferation in NCI-H292 cells but not NHBE cells. NSCLC also expressed elevated levels of the transcription factor E2F1. When NCI-H292 cells were transfected with E2F1 siRNA, both PTGS2 expression and PCSK activity were attenuated, arguing a pivotal role for E2F1 in the differential regulation of PCSKs by PTGS2. Our results highlight a novel role for PTGS2 in NSCLC and may provide a mechanism, whereby PTGS2 inhibitors suppress lung cancer cell growth.
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Affiliation(s)
- Kelly A Brant
- Department of Environmental and Occupational Health, University of Pittsburgh Graduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania 15219-3130
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63
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Huang YH, Lin KH, Liao CH, Lai MW, Tseng YH, Yeh CT. Furin overexpression suppresses tumor growth and predicts a better postoperative disease-free survival in hepatocellular carcinoma. PLoS One 2012; 7:e40738. [PMID: 22808247 PMCID: PMC3393699 DOI: 10.1371/journal.pone.0040738] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 06/12/2012] [Indexed: 12/22/2022] Open
Abstract
Furin is a member of the pro-protein convertase family. It processes several growth regulatory proteins into their active forms, which are critical to tumor progression, metastasis, and angiogenesis. Furin over-expression could occur in liver cancer and a previous study showed that over-expression of furin promoted HepG2 cell invasion in tail vein xenograft models. However, the clinical relevance of furin expression in hepatocellular carcinoma (HCC) remained unknown. Surprisingly, in a postoperative survival analysis for HCC patients, it was found that the tumor/non-tumor (T/N) ratio of furin expression ≥ 3.5 in HCC tissues predicted a better postoperative disease-free survival (DFS) (P = 0.010; log-rank test). Furthermore, subcutaneous xenograft experiments demonstrated a significant suppression effect of tumor growth in the furin-overexpressed xenografts (Huh7-Furin) compared to the mock control. Administration of a synthetic furin inhibitor for inhibition of the pro-protein convertase activity, decanoyl-Arg-Val-Lys-Arg-chloromethylketone (decRVKR-CMK), to the Huh7-Furin xenograft bearing mice restored the repression effect of tumor growth. In contrast, administration of decRVKR-CMK to the mock Huh7 xenograft bearing mice showed no change in growth rate. In conclusion, furin overexpression inhibited HCC tumor growth in a subcutaneous xenograft model and predicted a better postoperative DFS in clinical analysis.
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Affiliation(s)
- Ya-Hui Huang
- Department of Hepato-Gastroenterology, Liver Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kwang-Huei Lin
- Department of Biochemistry, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chen-Hsin Liao
- Department of Biochemistry, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Ming-Wei Lai
- Department of Pediatric Gastroenterology, Chang Gung Children Hospital, Taoyuan, Taiwan
| | - Yi-Hsin Tseng
- Department of Biochemistry, School of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chau-Ting Yeh
- Department of Hepato-Gastroenterology, Liver Research Center, Chang Gung Memorial Hospital, Taoyuan, Taiwan
- Molecular Medicine Research Center, Chang Gung University, Taoyuan, Taiwan
- * E-mail:
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64
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Seidah NG, Prat A. The biology and therapeutic targeting of the proprotein convertases. Nat Rev Drug Discov 2012; 11:367-83. [PMID: 22679642 DOI: 10.1038/nrd3699] [Citation(s) in RCA: 588] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The mammalian proprotein convertases constitute a family of nine secretory serine proteases that are related to bacterial subtilisin and yeast kexin. Seven of these (proprotein convertase 1 (PC1), PC2, furin, PC4, PC5, paired basic amino acid cleaving enzyme 4 (PACE4) and PC7) activate cellular and pathogenic precursor proteins by cleavage at single or paired basic residues, whereas subtilisin kexin isozyme 1 (SKI-1) and proprotein convertase subtilisin kexin 9 (PCSK9) regulate cholesterol and/or lipid homeostasis via cleavage at non-basic residues or through induced degradation of receptors. Proprotein convertases are now considered to be attractive targets for the development of powerful novel therapeutics. In this Review, we summarize the physiological functions and pathological implications of the proprotein convertases, and discuss proposed strategies to control some of their activities, including their therapeutic application and validation in selected disease states.
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Affiliation(s)
- Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal (affiliated to University of Montreal), 110 Pine Ave West, Montreal, Quebec H2W 1R7, Canada.
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López-Vallejo F, Martínez-Mayorga K. Furin inhibitors: importance of the positive formal charge and beyond. Bioorg Med Chem 2012; 20:4462-71. [PMID: 22682919 DOI: 10.1016/j.bmc.2012.05.029] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 05/03/2012] [Accepted: 05/12/2012] [Indexed: 02/02/2023]
Abstract
Furin is the prototype member of the proprotein convertases superfamily. Proprotein convertases are associated with hormonal response, neural degeneration, viral and bacterial activation, and cancer. Several studies over the last decade have examined small molecules, natural products, peptides and peptide derivatives as furin inhibitors. Currently, subnanomolar inhibition of furin is possible. Herein, we report the analysis of 115 furin inhibitors reported in the literature. Analysis of the physicochemical properties of these compounds highlights the dependence of the inhibitory potency with the total formal charge and also shows how the most potent (peptide-based) furin inhibitors have physicochemical properties similar to drugs. In addition, we report docking studies of 26 furin inhibitors using Glide XP. Inspection of binding interactions shows that the two putative binding modes derived from our study are reasonable. Analysis of the binding modes and protein-ligand interaction fingerprints, used here as postdocking procedure, shows that electrostatic interactions predominate on S1, S2 and S4 subsites but are seldom in S3. Our models also show that the benzimidamide group, present in the most active inhibitors, can be accommodated in the S1 subsite. These results are valuable for the design of new furin inhibitors.
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Affiliation(s)
- Fabian López-Vallejo
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987, USA
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Abstract
The proprotein convertases (PCs) are secretory mammalian serine proteinases related to bacterial subtilisin-like enzymes. The family of PCs comprises nine members, PC1/3, PC2, furin, PC4, PC5/6, PACE4, PC7, SKI-1/S1P, and PCSK9 (Fig. 3.1). While the first seven PCs cleave after single or paired basic residues, the last two cleave at non-basic residues and the last one PCSK9 only cleaves one substrate, itself, for its activation. The targets and substrates of these convertases are very varied covering many aspects of cellular biology and communication. While it took more than 22 years to begin to identify the first member in 1989-1990, in less than 14 years they were all characterized. So where are we 20 years later in 2011? We have now reached a level of maturity needed to begin to unravel the mechanisms behind the complex physiological functions of these PCs both in health and disease states. We are still far away from comprehensively understanding the various ramifications of their roles and to identify their physiological substrates unequivocally. How do these enzymes function in vivo? Are there other partners to be identified that would modulate their activity and/or cellular localization? Would non-toxic inhibitors/silencers of some PCs provide alternative therapies to control some pathologies and improve human health? Are there human SNPs or mutations in these PCs that correlate with disease, and can these help define the finesses of their functions and/or cellular sorting? The more we know about a given field, the more questions will arise, until we are convinced that we have cornered the important angles. And yet the future may well reserve for us many surprises that may allow new leaps in our understanding of the fascinating biology of these phylogenetically ancient eukaryotic proteases (Fig. 3.2) implicated in health and disease, which traffic through the cells via multiple sorting pathways (Fig. 3.3).
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Affiliation(s)
- Nabil G Seidah
- Biochemical Neuroendocrinology Laboratory, Clinical Research Institute of Montreal, Montreal, QC, Canada H2W 1R7.
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Affiliation(s)
- Andrew W Artenstein
- Center for Biodefense and Emerging Pathogens, Department of Medicine, Memorial Hospital of Rhode Island, Pawtucket 02860, USA.
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Applications of molecular imaging. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 95:237-98. [PMID: 21075334 DOI: 10.1016/b978-0-12-385071-3.00009-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Today molecular imaging technologies play a central role in clinical oncology. The use of imaging techniques in early cancer detection, treatment response, and new therapy development is steadily growing and has already significantly impacted on clinical management of cancer. In this chapter, we overview three different molecular imaging technologies used for the understanding of disease biomarkers, drug development, or monitoring therapeutic outcome. They are (1) optical imaging (bioluminescence and fluorescence imaging), (2) magnetic resonance imaging (MRI), and (3) nuclear imaging (e.g., single-photon emission computed tomography (SPECT) and positron emission tomography (PET)). We review the use of molecular reporters of biological processes (e.g., apoptosis and protein kinase activity) for high-throughput drug screening and new cancer therapies, diffusion MRI as a biomarker for early treatment response and PET and SPECT radioligands in oncology.
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69
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Molecular Validation of PACE4 as a Target in Prostate Cancer. Transl Oncol 2011; 4:157-72. [PMID: 21633671 DOI: 10.1593/tlo.10295] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 02/02/2011] [Accepted: 02/14/2011] [Indexed: 12/31/2022] Open
Abstract
Prostate cancer remains the single most prevalent cancer in men. Standard therapies are still limited and include androgen ablation that initially causes tumor regression. However, tumor cells eventually relapse and develop into a hormone-refractory prostate cancer. One of the current challenges in this disease is to define new therapeutic targets, which have been virtually unchanged in the past 30 years. Recent studies have suggested that the family of enzymes known as the proprotein convertases (PCs) is involved in various types of cancers and their progression. The present study examined PC expression in prostate cancer and validates one PC, namely PACE4, as a target. The evidence includes the observed high expression of PACE4 in all different clinical stages of human prostate tumor tissues. Gene silencing studies targeting PACE4 in the DU145 prostate cancer cell line produced cells (cell line 4-2) with slower proliferation rates, reduced clonogenic activity, and inability to grow as xenografts in nude mice. Gene expression and proteomic profiling of the 4-2 cell line reveals an increased expression of known cancer-related genes (e.g., GJA1, CD44, IGFBP6) that are downregulated in prostate cancer. Similarly, cancer genes whose expression is decreased in the 4-2 cell line were upregulated in prostate cancer (e.g., MUC1, IL6). The direct role of PACE4 in prostate cancer is most likely through the upregulated processing of growth factors or through the aberrant processing of growth factors leading to sustained cancer progression, suggesting that PACE4 holds a central role in prostate cancer.
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Dinosaurs and ancient civilizations: reflections on the treatment of cancer. Neoplasia 2011; 12:957-68. [PMID: 21170260 DOI: 10.1593/neo.101588] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 11/15/2010] [Accepted: 11/15/2010] [Indexed: 12/14/2022] Open
Abstract
Research efforts in the area of palaeopathology have been seen as an avenue to improve our understanding of the pathogenesis of cancer. Answers to questions of whether dinosaurs had cancer, or if cancer plagued ancient civilizations, have captured the imagination as well as the popular media. Evidence for dinosaurian cancer may indicate that cancer may have been with us from the dawn of time. Ancient recorded history suggests that past civilizations attempted to fight cancer with a variety of interventions. When contemplating the issue why a generalized cure for cancer has not been found, it might prove useful to reflect on the relatively limited time that this issue has been an agenda item of governmental attention as well as continued introduction of an every evolving myriad of manmade carcinogens relative to the total time cancer has been present on planet Earth. This article reflects on the history of cancer and the progress made following the initiation of the "era of cancer chemotherapy."
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Lindberg I, Appel JR. Inhibitor screening of proprotein convertases using positional scanning libraries. Methods Mol Biol 2011; 768:155-166. [PMID: 21805241 PMCID: PMC3845831 DOI: 10.1007/978-1-61779-204-5_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Proprotein convertases represent an important class of biosynthetic enzymes that are increasingly viewed as targets for therapeutic approaches to infection, cancer, and potentially endocrine disorders. The identification of potent inhibitors can be accomplished by screening synthetic combinatorial libraries containing thousands of small molecules to millions of peptides. In this chapter, the screening of positional scanning libraries is described for the identification of PC1/3 and PC2 inhibitors.
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Affiliation(s)
- Iris Lindberg
- School of Medicine Anatomy and Neurobiology, University of Maryland-Baltimore, Baltimore, MD 21201, USA.
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Kumar V, Behera R, Lohite K, Karnik S, Kundu GC. p38 kinase is crucial for osteopontin-induced furin expression that supports cervical cancer progression. Cancer Res 2010; 70:10381-91. [PMID: 20980434 DOI: 10.1158/0008-5472.can-10-1470] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
p38 kinases activated by growth factors, hormones, and environmental stresses exert diverse functions in regulating normal and malignant cell pathophysiology. Enhanced levels of activated p38 isoforms have been linked with poor prognosis in breast cancer, although the mechanistic basis for this association is poorly understood. In this study, we report that p38 activation in cervical cancer cells is driven by osteopontin (OPN), an extracellular matrix-associated cytokine that drives invasive progression. OPN regulates CD44-mediated p38 phosphorylation that induces NF-κB activation and NF-κB-dependent expression of furin, an extracellular protease implicated in human papilloma virus (HPV) processing that enhances cervical cancer cell motility. OPN induces CD44-mediated MKK3/6 phosphorylation which in turn phosphorylates p38 in these cells. OPN-induced furin expression and cell motility was impeded by blockades to MKK3/6, p38α/β or NF-κB signaling. In a mouse xenograft model of human cervical cancer, tumor growth was enhanced by OPN overexpression and blocked by short hairpin RNA (shRNA)-mediated OPN silencing. Furin overexpression similarly augmented tumor growth in the model, whereas blocking MKK3/6, p38, or furin reduced OPN-induced cervical tumor growth. Analysis of clinical specimens revealed that enhanced expression of OPN, phosphorylated NF-κB, p65, and furin correlated with cervical cancer progression, further strengthening the in vitro and in vivo results. In summary, our findings offer a proof of concept for targeting OPN and its downstream p38 signaling as a novel therapeutic strategy to manage cervical cancer.
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Affiliation(s)
- Vinit Kumar
- National Center for Cell Science, Pune, India
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The War on Cancer rages on. Neoplasia 2010; 11:1252-63. [PMID: 20019833 DOI: 10.1593/neo.91866] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 11/03/2009] [Accepted: 11/03/2009] [Indexed: 02/08/2023] Open
Abstract
In 1971, the "War on Cancer" was launched by the US government to cure cancer by the 200-year anniversary of the founding of the United States of America, 1976. This article briefly looks back at the progress that has been made in cancer research and compares progress made in other areas of human affliction. While progress has indeed been made, the battle continues to rage on.
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Portela-Gomes GM, Grimelius L, Wilander E, Stridsberg M. Granins and granin-related peptides in neuroendocrine tumours. ACTA ACUST UNITED AC 2010; 165:12-20. [PMID: 20211659 DOI: 10.1016/j.regpep.2010.02.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2009] [Revised: 02/06/2010] [Accepted: 02/25/2010] [Indexed: 10/19/2022]
Abstract
This review focus on neuroendocrine tumours (NETs), with special reference to the immunohistochemical analysis of granins and granin-related peptides and their usefulness in identifying and characterizing the great diversity of NET types. Granins, their derived peptides, and complex protein-processing enzyme systems that cleave granins and prohormones, have to some extent cell-specific expression patterns in normal and neoplastic NE cells. The marker most commonly used in routine histopathology to differentiate between non-NETs and NETs is chromogranin (Cg) A, to some extent CgB. Other members of the granin family may also be of diagnostic value by identifying special NET types, e.g. secretogranin (Sg) VI was only found in pancreatic NETs and phaeochromocytomas. SgIII has recently arisen as an important NET marker; it was strongly expressed in NETs, with some exceptions--phaeochromocytomas expressed few cells and parathyroid adenomas none. Some expression patterns of granin-related peptides seem valuable in differentiating between some benign and malignant NETs, some may also provide prognostic information, among which: well-differentiated NET types expressed more CgA epitopes than the poorly differentiated ones, except insulinomas, where the opposite was noted; medullary thyroid carcinomas containing few cells immunoreactive to a CgB antibody were related to a bad prognosis; C-terminal secretoneurin visualized a cell type related to malignancy in phaeochromocytomas. Further research will probably establish new staining patterns with marker functions for granins in NETs which may be of histopathological diagnostic value.
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Basak A, Khatib AM, Mohottalage D, Basak S, Kolajova M, Bag SS, Basak A. A novel enediynyl peptide inhibitor of furin that blocks processing of proPDGF-A, B and proVEGF-C. PLoS One 2009; 4:e7700. [PMID: 19956642 PMCID: PMC2778948 DOI: 10.1371/journal.pone.0007700] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 09/28/2009] [Indexed: 12/22/2022] Open
Abstract
Background Furin represents a crucial member of secretory mammalian subtilase, the Proprotein Convertase (PC) or Proprotein Convertase Subtilisin/Kexin (PCSK) superfamily. It has been linked to cancer, tumorgenesis, viral and bacterial pathogenesis. As a result it is considered a major target for intervention of these diseases. Methodology/Principal Findings Herein, we report, for the first time, the synthesis and biological evaluation of a newly designed potent furin inhibitor that contains a highly reactive beta-turn inducing and radical generating “enediynyl amino acid” (Eda) moiety. “Eda” was inserted between P1 and P1′ residues of hfurin98–112 peptide, derived from the primary cleavage site of furin's own prodomain. The resulting hexadecapeptide derivative inhibited furin in vitro with IC50 ∼40 nM when measured against the fluorogenic substrate Boc-RVRR-MCA. It also inhibited furin-mediated cleavage of a fluorogenic peptide derived from hSARS-CoV spike protein with IC50 ∼193 nM. Additionally it also blocked furin-processing of growth factors proPDGF-A, B and VEGF-C that are linked to tumor genesis and cancer. Circular dichroism study showed that this inhibitor displayed a predominantly beta-turn structure while western blots confirmed its ability to protect furin protein from self degradation. Conclusion/Significance These findings imply its potential as a therapeutic agent for intervention of cancer and other furin-associated diseases.
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Affiliation(s)
- Ajoy Basak
- Department of Biochemistry, Chronic Diseases Program, Regional Protein Chemistry Center, Ottawa Hospital Research Institute, University of Ottowa, Ottawa, Canada.
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Sun X, Essalmani R, Seidah NG, Prat A. The proprotein convertase PC5/6 is protective against intestinal tumorigenesis: in vivo mouse model. Mol Cancer 2009; 8:73. [PMID: 19737405 PMCID: PMC2746178 DOI: 10.1186/1476-4598-8-73] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 09/08/2009] [Indexed: 03/26/2023] Open
Abstract
Background The secretory basic amino acid-specific proprotein convertases (PCs) have often been associated with cancer/metastasis. By controlling the cleavage of cancer-associated proteins, PCs play key roles in multiple steps of cancer development. Most analyses of the implication of PCs in cancer/metastasis relied on the use of in vitro overexpression systems or inhibitors that can affect more than one PC. Aside from the role of furin in salivary gland tumorigenesis, no other in vivo genetic model of PC-knockout was reported in relation to cancer development. Results Since PC5/6 is highly expressed in the small intestine, the present study examined its in vivo role in intestinal tumorigenesis. Analysis of human intestinal tumors at various stages showed a systematic down-regulation of PC5/6 expression. Since gene inactivation of PC5/6 leads to lethality at birth, we generated mice lacking PC5/6 in enterocytes and analyzed the impact of the presence or absence of this PC in the mouse ApcMin/+ model that develops numerous adenocarcinomas along the intestinal tract. This resulted in viable mice with almost no expression of PC5/6 in small intestine, but with no overt phenotype. The data showed that by themselves ApcMin/+ tumors express lower levels of PC5/6 mRNA, and that the lack of PC5/6 in enterocytes results in a significantly higher tumor number in the duodenum, with a similar trend in other intestinal segments. Finally, the absence of PC5/6 is also associated with a premature mortality of ApcMin/+ mice. Conclusion Overall, these data suggest that intestinal PC5/6 is protective towards tumorigenesis, especially in mouse duodenum, and possibly in human colon.
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Affiliation(s)
- Xiaowei Sun
- Laboratory of Biochemical Neuroendocrinology, Clinical Research Institute of Montreal, affiliated to the University of Montreal, Montreal, Quebec, Canada.
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Dragulescu-Andrasi A, Liang G, Rao J. In vivo bioluminescence imaging of furin activity in breast cancer cells using bioluminogenic substrates. Bioconjug Chem 2009; 20:1660-6. [PMID: 19642690 DOI: 10.1021/bc9002508] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Furin, a proprotein convertases family endoprotease, processes numerous physiological substrates and is overexpressed in cancer and inflammatory conditions. Noninvasive imaging of furin activity will offer a valuable tool to probe furin function over the course of tumor growth and migration in the same animals in real time and directly assess the inhibition efficacy of drugs in vivo. Here, we report successful bioluminescence imaging of furin activity in xenografted MBA-MB-468 breast cancer tumors in mice with bioluminogenic probes. The probes are conjugates of furin substrate, a consensus amino acid motif R-X-K/R-R (X, any amino acid), with the firefly luciferase substrate D-aminoluciferin. In the presence of the luciferase reporter, the probes are unable to produce bioluminescent emission without furin activation. Blocking experiments with a furin inhibitor and control experiments with a scrambled probe showed that the bioluminescence emission in the presence of firefly luciferase is furin-dependent and specific. After furin activation, a 30-fold increase in the bioluminescent emission was observed in vitro, and on average, a 7-8-fold contrast between the probe and control was seen in the same tumor xenografts in mice. Direct imaging of furin activity may facilitate the study of furin function in tumorigenicity and the discovery of new drugs for furin-targeted cancer therapy.
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Affiliation(s)
- Anca Dragulescu-Andrasi
- Department of Radiology, Stanford University School of Medicine, Stanford, California 94305, USA
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Rholam M, Fahy C. Processing of peptide and hormone precursors at the dibasic cleavage sites. Cell Mol Life Sci 2009; 66:2075-91. [PMID: 19300906 PMCID: PMC11115611 DOI: 10.1007/s00018-009-0007-5] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 02/11/2009] [Accepted: 02/17/2009] [Indexed: 01/31/2023]
Abstract
Many functionally important cellular peptides and proteins, including hormones, neuropeptides, and growth factors, are synthesized as inactive precursor polypeptides, which require post-translational proteolytic processing to become biologically active polypeptides. This is achieved by the action of a relatively small number of proteases that belong to a family of seven subtilisin-like proprotein convertases (PCs) including furin. In view of this, this review focuses on the importance of privileged secondary structures and of given amino acid residues around basic cleavage sites in substrate recognition by these endoproteases. In addition to their participation in normal cell functions, PCs are crucial for the initiation and progress of many important diseases. Hence, these proteases constitute potential drug targets in medicine. Accordingly, this review also discusses the approaches used to shed light on the cleavage preference and the substrate specificity of the PCs, a prerequisite to select which PCs are promising drug targets in each disease.
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Affiliation(s)
- Mohamed Rholam
- Interfaces, Traitements, Organisation et Dynamique des Systrèmes, Université Paris Diderot (Paris 7), CNRS UMR 7086, Bâtiment Lavoisier, 15 rue Jean-Antoine de Baïf, 75205, Paris Cedex 13, France.
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Tang R, Rosen SD. Functional consequences of the subdomain organization of the sulfs. J Biol Chem 2009; 284:21505-14. [PMID: 19520866 DOI: 10.1074/jbc.m109.028472] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sulf-1 and Sulf-2 are novel extracellular sulfatases that act on internal glucosamine 6-O-sulfate modifications within heparan sulfate proteoglycans and regulate their interactions with various signaling molecules, including Wnt ligands. Although the Sulfs are multidomain proteins, there is limited information available about how the subdomains contribute to their enzymatic and signaling activities. In this study, we found that both human Sulfs were synthesized as prepro-enzymes and cleaved by a furin-type proteinase to form disulfide-bond linked heterodimers of 75- and 50-kDa subunits. The mature Sulfs were secreted into conditioned medium, as well as retained on the cell membrane. Although the catalytic center resides in the N-terminal 75-kDa subunit, the C-terminal 50-kDa subunit was indispensable for both arylsufatase and glucosamine 6-O-sulfate-endosulfatase activity. We found that the hydrophilic regions of the Sulfs were essential for endosulfatase activity but not for arylsulfatase activity. Using Edman sequencing, we identified furin-type proteinase cleavage sites in Sulf-1 and Sulf-2. Deletion of these sequences resulted in uncleavable forms of Sulfs. The uncleavable Sulfs retained enzymatic activity. However, they were unable to potentiate Wnt signaling, which may be due to their defective localization into lipid rafts on the plasma membrane.
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Affiliation(s)
- Renhong Tang
- Department of Anatomy, University of California, San Francisco, California 94143, USA
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Neoplasia: the second decade. Neoplasia 2009; 10:1314-24. [PMID: 19048110 DOI: 10.1593/neo.81372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 10/27/2008] [Accepted: 10/27/2008] [Indexed: 12/30/2022] Open
Abstract
This issue marks the end of the 10-year anniversary of Neoplasia where we have seen exciting growth in both number of submitted and published articles in Neoplasia. Neoplasia was first published in 1999. During the past 10 years, Neoplasia has dynamically adapted to the needs of the cancer research community as technologies have advanced. Neoplasia is currently providing access to articles through PubMed Central to continue to facilitate rapid broad-based dissemination of published findings to the scientific community through an Open Access model. This has in part helped Neoplasia to achieve an improved impact factor this past year, demonstrating that the manuscripts published by Neoplasia are of great interest to the overall cancer research community. This past year, Neoplasia received a record number of articles for review and has had a 21% increase in the number of published articles.
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Komiyama T, Coppola JM, Larsen MJ, van Dort ME, Ross BD, Day R, Rehemtulla A, Fuller RS. Inhibition of furin/proprotein convertase-catalyzed surface and intracellular processing by small molecules. J Biol Chem 2009; 284:15729-38. [PMID: 19332539 DOI: 10.1074/jbc.m901540200] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Furin is a ubiquitously expressed proprotein convertase (PC) that plays a vital role in numerous disease processes including cancer metastasis, bacterial toxin activation (e.g. anthrax and Pseudomonas), and viral propagation (e.g. avian influenza and human immunodeficiency virus). To identify small molecule inhibitors of furin and related processing enzymes, we performed high-throughput screens of chemical diversity libraries utilizing both enzyme-based and cell-based assays. The screens identified partially overlapping sets of compounds that were further characterized for affinity, mechanism, and efficacy in additional cellular processing assays. Dicoumarols were identified as a class of compounds that inhibited furin non-competitively and reversibly with Ki values in the micromolar range. These compounds inhibited furin/furin-like activity both at the cell surface (protecting against anthrax toxin) and in the secretory pathway (blocking processing of the metastasis factor membrane-type 1 matrix metalloproteinase/MT1-MMP) at concentrations close to Ki values. Compounds tested exhibited distinct patterns of inhibition of other furin-family PCs (rat PACE4, human PC5/6 and human PC7), showing that dicoumarol derivatives might be developed as either generic or selective inhibitors of the PCs. The extensive clinical use, high bioavailability and relatively low toxicity of dicoumarols suggests that the dicoumarol structure will be a good starting point for development of drug-like inhibitors of furin and other PCs that can act both intracellularly and at the cell surface.
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Affiliation(s)
- Tomoko Komiyama
- Departments of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan 48109-0606, USA
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Abstract
PURPOSE OF REVIEW To describe recent advances in the processing of gastrointestinal hormones, and the consequences for human disease of mutations in the enzymes involved. RECENT FINDINGS Although gastrointestinal prohormones were long regarded as devoid of biological activity, recent data indicate that the prohormones for both gastrin and gastrin-releasing peptide are bioactive, through different receptors from the mature hormones. Mutations in the family of prohormone convertases responsible for the initial steps in the processing of gastrointestinal hormones are associated with several different pathophysiological conditions in humans. SUMMARY Human mutational studies, when taken together with the phenotypes observed in mice deficient in the prohormone convertases, emphasize the crucial importance of the processing enzymes in mammalian biology. Although the phenotypes may often be ascribed to defective production of a mature hormone or growth factor, the recognition that the precursors are independently bioactive suggests that the increased precursor concentrations may also contribute to the symptoms. The observation that the precursors often act through different receptors from the mature hormones may permit the development of precursor-selective antagonists for therapeutic use.
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Affiliation(s)
- Suzana Kovac
- University of Melbourne, Department of Surgery, Austin Health, Heidelberg, Victoria, Australia
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